#! perl -slw
use strict;
use Time::HiRes qw[ time ];
use Data::Dump qw[ pp ];
use List::Util qw[ sum ];

sub coffOfVar {
    my $mean = sum( @_ ) / @_;
    return 0 unless $mean;
    my @dif2s = map{ ( $_ - $mean )**2 } @_;
    my $stddev = sum( @dif2s ) / $#_;
    return $stddev / $mean
}

my @data;
push @data, [ map rand( 2000 )-1000, 1..7 ] for 1 .. 55*1024;

my $start = time;
my @results;
push @results, sprintf '%.5E', coffOfVar( @$_ ) for @data;

printf "Took %.2f seconds to find the coffOfVar of %d datasets\n",
    time - $start, scalar @data;

__END__
C:\test>802855.pl
Took 0.59 seconds to find the coffOfVar of 56320 datasets